Fabrication and characterisation of a double-clamped beam structure as a control gate for a high-speed non-volatile memory device

• Published in: Microelectronic engineering 2014-02, Vol.114, p.22-25
• Main Authors: García-Ramírez, M.A., Ghiass, A.M., Moktadir, Z., Tsuchiya, Y., Mizuta, H.
• Format: Article
• Language: English
• Subjects: Aluminum; Applied sciences; Beams (structural); Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Data storage; Deposition; Electronics; Exact sciences and technology; Gates; High speed; Hybrid devices; Integrated circuits; Integrated circuits by function (including memories and processors); Materials science; Memory devices; Meters; Methods of deposition of films and coatings; film growth and epitaxy; Microelectronic fabrication (materials and surfaces technology); Molecular, atomic, ion, and chemical beam epitaxy; Non-volatile memories; Physics; Plasma processes; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Short-range forces; Van der Waals forces
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2013.09.002

[Display omitted] •A suspended double-clamped beam for a NV-Memory is fabricated and characterised.•The recipe developed to suspend the beam structure shows a high selectivity rate.•Once biased, the beam pulls-in but due to the short-range forces pull-out was missing.•Short-range forces such as the van der Waals are stronger when in contact (Al/SiO2).•A relationship to overcome such forces is obtained through 2D-FEM analysis. We report the fabrication and characterisation of a suspended double-clamped beam structure that is implemented as a movable control gate within a hybrid high-speed non-volatile memory device. This structure features a foundation of SiO2/Si layers over which a poly-Si layer (sacrificial) is deposited by using a low-pressure chemical vapour deposition (LPCVD) and as a movable control gate, an aluminium (Al) layer is deposited by using an e-beam evaporator. The Al layer is patterned with double-clamped beam structures by using photolithography and through a combination of wet and dry etching processes, the structures are successfully suspended and characterised by using a C–V meter. From the structure characterisation, the pull-in curve is successfully obtained and due to unexpected large short-range forces such as the van der Waals forces, the pull-out curve is not observed. In order to clarify this issue, a numerical analysis is performed in which the structural materials under test shown the influence of such short-range forces on the structure and a solution to override them is proposed.